diff options
Diffstat (limited to 'geom.lua')
-rw-r--r-- | geom.lua | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/geom.lua b/geom.lua index 20cc5dd..7dd6628 100644 --- a/geom.lua +++ b/geom.lua @@ -7,7 +7,7 @@ function geom.on_shape(x,y, drawing, shape) return geom.on_line(x,y, drawing, shape) elseif shape.mode == 'manhattan' then return x == drawing.points[shape.p1].x or y == drawing.points[shape.p1].y - elseif shape.mode == 'polygon' then + elseif shape.mode == 'polygon' or shape.mode == 'rectangle' or shape.mode == 'square' then return geom.on_polygon(x,y, drawing, shape) elseif shape.mode == 'circle' then local center = drawing.points[shape.center] @@ -82,6 +82,28 @@ function geom.on_polygon(x,y, drawing, shape) return geom.on_line(x,y, drawing, {p1=shape.vertices[1], p2=shape.vertices[#shape.vertices]}) end +-- are (x3,y3) and (x4,y4) on the same side of the line between (x1,y1) and (x2,y2) +function geom.same_side(x1,y1, x2,y2, x3,y3, x4,y4) + if x1 == x2 then + return math.sign(x3-x1) == math.sign(x4-x1) + end + if y1 == y2 then + return math.sign(y3-y1) == math.sign(y4-y1) + end + local m = (y2-y1)/(x2-x1) + return math.sign(m*(x3-x1) + y1-y3) == math.sign(m*(x4-x1) + y1-y4) +end + +function math.sign(x) + if x > 0 then + return 1 + elseif x == 0 then + return 0 + elseif x < 0 then + return -1 + end +end + function geom.angle_with_hint(x1, y1, x2, y2, hint) local result = geom.angle(x1,y1, x2,y2) if hint then |